A strong demand exists among medical specialists for a nonantigenic, nonmigratory, biocompatible filler material for correcting soft tissue deficiencies. Historically, the correction of contour deficiencies with various filler materials has met with failure or limited success. Early injectable filler materials included oils, mica, and autologous fat. Prime F., "The Prevention of Postoperative Adhesions Between the Cortex and Dura", Univ. Penn. Med. Bull., 20: 57-61 (1909); Chao, Y., et al., "A New Method of Preventing Adhesions: The Use of Amniplastin After Craniotomy", Br. Med. J., 1: 517-19 (1940); Muscona, R., "Free Fat Injections for The Correction of Hemifacial Atrophy", Plast. Reconstr. Surg., 85(3):501 (1989). Synthetic biocompatible filler materials such as silicone fluid and Teflon.RTM. have also met with limited success. Both of those materials migrate from the injection site to other parts of the body with deleterious results. Symmers, W., "Silicone Mastitis In "Topless" Waitresses And Some Varieties of Foreign Body Mastitis", Br. Med. J., 3: 19 (1968)
Presently, bovine dermal collagen is the most widely used filler material and is used in the form of an injectable protein. Unfortunately, it is antigenic and therefore is attacked by the body's immune system. The foreign collagen is broken down so that periodic replacement treatments are required. Trenthan, D. E, "Adverse Reactions To Bovine Collagen Implants," Arch. Dermatol., 122: 643-44 (1986). Patients treated with bovine dermal collagen have complained of adverse results ranging from allergic responses to rare autoimmune diseases. Press Release, "Collagen Wins--Court Case Filed By Woman claiming Treatments Are Defective", United Press International, Oct. 16, 1991.
Recently, a new synthetic polymer called Bioplastique.RTM. has been introduced to the market for permanent soft tissue augmentation through injection. Unfortunately, Bioplastique.RTM. is largely ineffective since it cannot be injected into the dermis, but must be injected subdermally. This is due to the fact that Bioplastique.RTM. consists of 100 to 400 .mu.m particles of dimethylsiloxame suspended in a biodegradable hydrogel. These particles are too large to enter the dermis. Ersek, R. A., "Bioplastique.RTM.: A New Biphasic Polymer For Minimally Invasive Injection Implantation", Aesth, Plast. Surg., 16: 59-65 (1992).
A strong need also exists for biomedical implants and implant coatings that are biocompatible, nontoxic, and structurally and chemically stable. Such implants and coatings would replace bone and cartilage in applications ranging from maxillofacial reconstruction to total joint replacement.
The present invention is a new nonantigenic keratinous protein material that is derived from a compatible donor, or from the potential recipient of the material. Consequently, the material does not invoke a deleterious immunological reaction in a recipient, thus meeting a long-standing need for both filler material for correcting soft tissue deficiencies and for an implant material. More specifically, keratinous protein is advantageous as used in the present invention because it does not auto-biodegrade due to either the enzymatic systems or the immune system of the body, thus making it permanent for the life of the patient and nonantigenic. Furthermore, the protein particles of this invention are small enough for injection into the dermis.